Why Must an Engineered DNA Polymerase Be Used in PCR

Why must an engineered DNA polymerase be used in PCR and not the one that occurs naturally?

A) It needs to work at very cold temperatures.
B) It needs to attach to DNA without a primer.
C) It must work in the 3' to 5' direction adding nucleotides to the 5' end.
D) It must work on single stranded DNA at high temperatures and attach to an oligonucleotide primer.
E) It must attach without a primer, work in the 3' to 5' direction and function at very cold temperatures.